This invention relates to the feeding of molten strands of plastic to a trough where the strands are solidified, and more particularly to a slanted drainage trough which extends under the fall line of stands that emerge from nozzles.
In the use of troughs to collect molten plastic strands, the trough is pivoted into position to receive the strands and is supplied with a coolant, such as water, which is directed to the upper end of the trough and drains along its slanted face.
A representative drainage trough for molten plastic strands is disclosed in German patent No. 2,503,455. The drainage trough of this patent is used with a pivotal flap. The flap is mounted on a perpendicular axle with respect to the trough at its upper end. The flap can be pivoted to occupy one of two positions. In the operating position the flap is pivoted into contact with the drainage trough to catch the strands emerging from the nozzles and conduct them to the coolant water that is applied to the product for solidification of the strands. In the non-operating position, the flap is pivoted away from the trough so that the strands emerging from the nozzles fall between the flap and the trough. During initial operation it is necessary to deflect the material emerging from the nozzles in order to avoid the contamination associated with the initial flow, as well as to allow the composition which is emerging from the nozzles to reach a uniform state. In the deflection of the strands from the trough, they are conducted through a relatively narrow shaft formed between the flap and the reverse side of the trough. Since the initial flow of the contaminated and non-uniform material is through the drainage shaft, it is necessary to clean the shaft from time to time. However, because of the construction of the flap relative to the trough in forming the shaft, cleaning is difficult because the interior of the shaft is relatively inaccessible.
Accordingly, it is an object of the invention to facilitate the feed and cooling of molten strands of plastic. A related object is to avoid the feed of contaminated and non-uniform plastic material to a drainage trough where molten stands are subjected to cooling.
Another object of the invention is to achieve the feed of relatively uniform stands of plastic material to a drainage trough for cooling without requiring the periodic cleaning and removal of contaminated and non-uniform materials that flow during initial operation of the cooling trough.
Still another object of the invention is to avoid the need for pivotal flaps in the operation of cooling troughs and the associated inaccessibility from the standpoint of cleaning and maintenance that is occasioned by the presence of such a flap.